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Groups > comp.lang.java.programmer > #24615

Re: convert byte array to hex string using BigInteger

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On 6/29/2013 12:10 PM, Stanimir Stamenkov wrote:
> Wed, 26 Jun 2013 22:12:30 -0400, /Arne Vajhøj/:
>
>> You have already received several working solutions.
>>
>> I will strongly recommend you drop the idea about using
>> BigInteger for this.
>>
>> It becomes extremely tricky to get it right - you have already
>> found the sign problem - next problem will be the leading zero
>> problem.
>>
>> [... bunch of code...]
>
> I may be dense, but I didn't got why using BigInteger is not good?
> What's wrong with the following, for example:
>
>      byte[] val;
>      ...
>      String.format("%064x", new BigInteger(1, val));

You will not be able to get back to the same byte array with that.

> I guess one could come up with a method like:
>
>      String toHexString(byte[] val, int len) {
>          BigInteger num = new BigInteger(1, val);
>          return (len > 0) ? String.format("%0" + len + "x", num)
>                           : String.format("%x", num);
>      }
>
> Doesn't it appear sufficient?

It seems to work.

I would probably drop the len argument and use 2*val.length.

But it is still not as simple as the DatatypeConverter.

Arne

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Thread

convert byte array to hex string using BigInteger Laura Schmidt <ls@mailinator.com> - 2013-06-20 14:03 +0200
  Re: convert byte array to hex string using BigInteger Eric Sosman <esosman@comcast-dot-net.invalid> - 2013-06-20 09:03 -0400
  Re: convert byte array to hex string using BigInteger rossum <rossum48@coldmail.com> - 2013-06-20 14:09 +0100
    Re: convert byte array to hex string using BigInteger Laura Schmidt <ls@mailinator.com> - 2013-06-20 15:32 +0200
      Re: convert byte array to hex string using BigInteger rossum <rossum48@coldmail.com> - 2013-06-20 15:44 +0100
      Re: convert byte array to hex string using BigInteger lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-20 19:22 +0100
        Re: convert byte array to hex string using BigInteger markspace <markspace@nospam.nospam> - 2013-06-20 11:56 -0700
          Re: convert byte array to hex string using BigInteger lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-20 20:43 +0100
        Re: convert byte array to hex string using BigInteger Lew <lewbloch@gmail.com> - 2013-06-20 13:39 -0700
          Re: convert byte array to hex string using BigInteger lipska the kat <"nospam at neversurrender dot co dot uk"> - 2013-06-21 08:17 +0100
        Re: convert byte array to hex string using BigInteger Arne Vajhøj <arne@vajhoej.dk> - 2013-06-26 22:16 -0400
  Re: convert byte array to hex string using BigInteger Joerg Meier <joergmmeier@arcor.de> - 2013-06-20 22:09 +0200
  Re: convert byte array to hex string using BigInteger Roedy Green <see_website@mindprod.com.invalid> - 2013-06-21 14:51 -0700
    Re: convert byte array to hex string using BigInteger Joerg Meier <joergmmeier@arcor.de> - 2013-06-22 00:26 +0200
      Re: convert byte array to hex string using BigInteger Roedy Green <see_website@mindprod.com.invalid> - 2013-06-23 08:49 -0700
        Re: convert byte array to hex string using BigInteger Joerg Meier <joergmmeier@arcor.de> - 2013-06-23 22:37 +0200
      Re: convert byte array to hex string using BigInteger Roedy Green <see_website@mindprod.com.invalid> - 2013-06-23 12:40 -0700
        Re: convert byte array to hex string using BigInteger Joerg Meier <joergmmeier@arcor.de> - 2013-06-23 22:41 +0200
  Re: convert byte array to hex string using BigInteger Arne Vajhøj <arne@vajhoej.dk> - 2013-06-26 22:12 -0400
    Re: convert byte array to hex string using BigInteger Arne Vajhøj <arne@vajhoej.dk> - 2013-06-26 22:20 -0400
    Re: convert byte array to hex string using BigInteger Laura Schmidt <ls@mailinator.com> - 2013-06-28 07:55 +0200
      Re: convert byte array to hex string using BigInteger Joerg Meier <joergmmeier@arcor.de> - 2013-06-29 00:01 +0200
    Re: convert byte array to hex string using BigInteger Stanimir Stamenkov <s7an10@netscape.net> - 2013-06-29 19:10 +0300
      Re: convert byte array to hex string using BigInteger Arne Vajhøj <arne@vajhoej.dk> - 2013-07-03 22:24 -0400
  Re: convert byte array to hex string using BigInteger aydin.k.abadi@gmail.com - 2013-11-23 16:40 -0800
  Re: convert byte array to hex string using BigInteger aydin.k.abadi@gmail.com - 2013-11-23 16:43 -0800
    Re: convert byte array to hex string using BigInteger Andreas Leitgeb <avl@gamma.logic.tuwien.ac.at> - 2013-11-24 10:43 +0000

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